My last two log-entries about plums and elderberries drew a lot of visitors. The articles led to some discussions on winemaking forums but also made some readers write me about fermentation starting problems.

Now if fermentation does not start in a relatively short time it can lead to spoilage of your must, something we absolutely want to prevent happening. So we have to make sure that the habitat for your yeast will be at an optimum. The acidity should be right, there should be nutrient and sugar and of course the temperature should be right.

Now if we winemakers made shure that the habitat for your yeast (juice or pulp) is at an optimum condition the addition of yeast will lead to signs of fermentation in a short time. A number of factors kan however block the fermenation.

One of these factors is the yeast itself.

The yeast we buy at our local home brew shop is normally kept in optimum circumstances meaning dry and cool. As well in the shops as at home yeast should be kept air-tight in the fridge.Often this is not the case. I have visisted home brew shops myself where the yeast was kept on shelves and not in a fridge. And in the hot summer months temperatures can rise to an unacceptable level for keeping your yeast healthy. The shelf life will therefore ceratinly be lower as expected.

Opening a sachet for getting some of the yeast out will also introduce air into the sachet and therefore humidity. Dried yeast cells will be awakened by the moisture. There is however no nutrient present and those cells will die. Therefore the remaining yeast in the sachet can be of lower quality. This is the reason it is often recommended to use the complete sachet.

And then there is of course the moment the yeast will be innoculated. If the dried yeast enters a wet environment (our must or pulp) it will immediately absorb as much as moisture as possible. The yeast will act as a sponge. It will therefore also absorb elements in the moisture it would normally not absorb. These elements may inhibit the yeast. This is the reason a fermentation might start very slow or not at all.

If we for example sprinkle the dry yeast directly on our must it will immediately absorb the must and try to become active. But the must will contain sulphite. Now normally wine-yeast is sulphite-resistant but then we are talking about yeast in active form. Dried yeast that aborbs sulphite might become inactive or even die.

This is the reason manufacturers tell you to de-hydrate yeast in some plain water.

So to give our yeast the best headstart for a healthy fermentation we make sure that before adding it to the must we will give it an optimum habitat to recuperate from de-hydrating.

So we will make an ideal must for our yeast. We call it a yeast starter.

Now winemaking is a mixture of art and science. The art manifests in making a fantastic wine from our initial juice. The science manifests in calculations about acidity, SG etc. But also in carefull planning.

A yeast starter will be made one to two days in advance of the processing of the fuits for our wine. We will then be sure that we add a vigorous fermenting starter to our must.

In the supermarket we buy pure apple juice or grape juice. If you are starting a white wine make sure you buy a white grape juice to prevent coloring of the must. Apple juice is the most neutral juice but grape juice will add some body to your wine. Be very alert that the are no conserving products are used.

Measure 1 liter juice and put it on a low fire. Meanwhile measure 120 to 150 grams of sugar and 2 grams citric acid or tartaric acid. While stiring the ingredients in bring the juice to a boil. When boiling let it cool down again. I normally do this by putting the pan in the sink with cold water and stir. When the temperature is down again to about 40 degrees celsius add 2 grams yeast nutrient. While stirring let it cool down further to 20 to 25 degrees celsius. All ingredients should be well dissolved by now.

Meanwhile clean a plastic bottle and sanitise it with water with some citric acid dissolved and sulphite. Clean the entire bottle by totally filling it.

Now when the starter must has cooled down to 20-25 degrees celsius empty the bottle with the sulphite solution and rinse it a few times. Put a funnel on and sprinkle a few tea spoons yeast (or the complete sachet) in and then add the starter must.

Make sure the temperature is not to high as yeast will die at temperatures in access of 32 degrees celsius.

By splashing the yeast and the starter-must through the funnel oxygen will be introduced which will help the yeast at reproduction. Put the stopper on the bottle and shake well. This will introduce even more oxygen.

Then loosen the stopper and replace it with some cotton or a piece of kitchen paper tightened with a rubber band. This way no fruit-flies or other insects can get into the starter, CO2 kan escape and oxygen can enter.

After a while fermentation will start. You can observe this by the layer of foam that will occur and the small bubbles of CO2 that will rise in the starter.

If within a few hours or a night nothing will happen you know that the yeast was dead or there were to few good yeast cells left to start the process. You will have still time to add another sachet of yeast.

Meanwhile prepare the must for the wine-to-be with bringing the SG up to level, correcting the acidity, adding pecto-enzymes and sulphite.

In the most ideal situation you will have your yeast starter prepared in a 3 to 5 liter bottle. So now add half a liter of the wine-must to the starter. Wait until fermentation is vigorous again and then add another liter.Again wait until fermentation is vigorous again. The yeast is now totally accustomed to the must it is going to live in. You will have a 2 and a half liter vigorous fermenting yeast starter which you can now safely add to the wine-must.

If you have made the starter in a smaller bottle then pour it like that in the must. It will take a while until the yeast is used to its new environment but after a few hours you should notice some activity.

Afterword:By using a yeast starter you are sure that you are adding a strong, healthy fermenting yeast to your must. Therefore the must itself will start fermenting easily. If there should occur any problems with fermentation you can be sure it is not the yeast that is causing the problems.